2 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
13 #include <linux/module.h>
15 #include <linux/refcount.h>
16 #include <linux/scatterlist.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
21 #include <media/videobuf2-v4l2.h>
22 #include <media/videobuf2-memops.h>
23 #include <media/videobuf2-dma-sg.h>
26 module_param(debug, int, 0644);
28 #define dprintk(level, fmt, arg...) \
31 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
34 struct vb2_dma_sg_buf {
38 struct frame_vector *vec;
40 enum dma_data_direction dma_dir;
41 struct sg_table sg_table;
43 * This will point to sg_table when used with the MMAP or USERPTR
44 * memory model, and to the dma_buf sglist when used with the
45 * DMABUF memory model.
47 struct sg_table *dma_sgt;
49 unsigned int num_pages;
51 struct vb2_vmarea_handler handler;
53 struct dma_buf_attachment *db_attach;
56 static void vb2_dma_sg_put(void *buf_priv);
58 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
61 unsigned int last_page = 0;
62 unsigned long size = buf->size;
69 order = get_order(size);
70 /* Don't over allocate*/
71 if ((PAGE_SIZE << order) > size)
76 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
77 __GFP_NOWARN | gfp_flags, order);
83 __free_page(buf->pages[last_page]);
89 split_page(pages, order);
90 for (i = 0; i < (1 << order); i++)
91 buf->pages[last_page++] = &pages[i];
93 size -= PAGE_SIZE << order;
99 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
100 unsigned long size, enum dma_data_direction dma_dir,
103 struct vb2_dma_sg_buf *buf;
104 struct sg_table *sgt;
109 return ERR_PTR(-EINVAL);
111 buf = kzalloc(sizeof *buf, GFP_KERNEL);
113 return ERR_PTR(-ENOMEM);
116 buf->dma_dir = dma_dir;
119 /* size is already page aligned */
120 buf->num_pages = size >> PAGE_SHIFT;
121 buf->dma_sgt = &buf->sg_table;
124 * NOTE: dma-sg allocates memory using the page allocator directly, so
125 * there is no memory consistency guarantee, hence dma-sg ignores DMA
126 * attributes passed from the upper layer.
128 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
129 GFP_KERNEL | __GFP_ZERO);
131 goto fail_pages_array_alloc;
133 ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
135 goto fail_pages_alloc;
137 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
138 buf->num_pages, 0, size, GFP_KERNEL);
140 goto fail_table_alloc;
142 /* Prevent the device from being released while the buffer is used */
143 buf->dev = get_device(dev);
145 sgt = &buf->sg_table;
147 * No need to sync to the device, this will happen later when the
148 * prepare() memop is called.
150 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
151 DMA_ATTR_SKIP_CPU_SYNC))
154 buf->handler.refcount = &buf->refcount;
155 buf->handler.put = vb2_dma_sg_put;
156 buf->handler.arg = buf;
158 refcount_set(&buf->refcount, 1);
160 dprintk(1, "%s: Allocated buffer of %d pages\n",
161 __func__, buf->num_pages);
165 put_device(buf->dev);
166 sg_free_table(buf->dma_sgt);
168 num_pages = buf->num_pages;
170 __free_page(buf->pages[num_pages]);
173 fail_pages_array_alloc:
175 return ERR_PTR(-ENOMEM);
178 static void vb2_dma_sg_put(void *buf_priv)
180 struct vb2_dma_sg_buf *buf = buf_priv;
181 struct sg_table *sgt = &buf->sg_table;
182 int i = buf->num_pages;
184 if (refcount_dec_and_test(&buf->refcount)) {
185 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
187 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
188 DMA_ATTR_SKIP_CPU_SYNC);
190 vm_unmap_ram(buf->vaddr, buf->num_pages);
191 sg_free_table(buf->dma_sgt);
193 __free_page(buf->pages[i]);
195 put_device(buf->dev);
200 static void vb2_dma_sg_prepare(void *buf_priv)
202 struct vb2_dma_sg_buf *buf = buf_priv;
203 struct sg_table *sgt = buf->dma_sgt;
205 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
208 static void vb2_dma_sg_finish(void *buf_priv)
210 struct vb2_dma_sg_buf *buf = buf_priv;
211 struct sg_table *sgt = buf->dma_sgt;
213 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
216 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
218 enum dma_data_direction dma_dir)
220 struct vb2_dma_sg_buf *buf;
221 struct sg_table *sgt;
222 struct frame_vector *vec;
225 return ERR_PTR(-EINVAL);
227 buf = kzalloc(sizeof *buf, GFP_KERNEL);
229 return ERR_PTR(-ENOMEM);
233 buf->dma_dir = dma_dir;
234 buf->offset = vaddr & ~PAGE_MASK;
236 buf->dma_sgt = &buf->sg_table;
237 vec = vb2_create_framevec(vaddr, size);
239 goto userptr_fail_pfnvec;
242 buf->pages = frame_vector_pages(vec);
243 if (IS_ERR(buf->pages))
244 goto userptr_fail_sgtable;
245 buf->num_pages = frame_vector_count(vec);
247 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
248 buf->num_pages, buf->offset, size, 0))
249 goto userptr_fail_sgtable;
251 sgt = &buf->sg_table;
253 * No need to sync to the device, this will happen later when the
254 * prepare() memop is called.
256 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
257 DMA_ATTR_SKIP_CPU_SYNC))
258 goto userptr_fail_map;
263 sg_free_table(&buf->sg_table);
264 userptr_fail_sgtable:
265 vb2_destroy_framevec(vec);
268 return ERR_PTR(-ENOMEM);
272 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
275 static void vb2_dma_sg_put_userptr(void *buf_priv)
277 struct vb2_dma_sg_buf *buf = buf_priv;
278 struct sg_table *sgt = &buf->sg_table;
279 int i = buf->num_pages;
281 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
282 __func__, buf->num_pages);
283 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
285 vm_unmap_ram(buf->vaddr, buf->num_pages);
286 sg_free_table(buf->dma_sgt);
287 if (buf->dma_dir == DMA_FROM_DEVICE ||
288 buf->dma_dir == DMA_BIDIRECTIONAL)
290 set_page_dirty_lock(buf->pages[i]);
291 vb2_destroy_framevec(buf->vec);
295 static void *vb2_dma_sg_vaddr(void *buf_priv)
297 struct vb2_dma_sg_buf *buf = buf_priv;
303 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
305 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);
308 /* add offset in case userptr is not page-aligned */
309 return buf->vaddr ? buf->vaddr + buf->offset : NULL;
312 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
314 struct vb2_dma_sg_buf *buf = buf_priv;
316 return refcount_read(&buf->refcount);
319 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
321 struct vb2_dma_sg_buf *buf = buf_priv;
325 printk(KERN_ERR "No memory to map\n");
329 err = vm_map_pages(vma, buf->pages, buf->num_pages);
331 printk(KERN_ERR "Remapping memory, error: %d\n", err);
336 * Use common vm_area operations to track buffer refcount.
338 vma->vm_private_data = &buf->handler;
339 vma->vm_ops = &vb2_common_vm_ops;
341 vma->vm_ops->open(vma);
346 /*********************************************/
347 /* DMABUF ops for exporters */
348 /*********************************************/
350 struct vb2_dma_sg_attachment {
352 enum dma_data_direction dma_dir;
355 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf,
356 struct dma_buf_attachment *dbuf_attach)
358 struct vb2_dma_sg_attachment *attach;
360 struct scatterlist *rd, *wr;
361 struct sg_table *sgt;
362 struct vb2_dma_sg_buf *buf = dbuf->priv;
365 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
370 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
371 * map the same scatter list to multiple attachments at the same time.
373 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
379 rd = buf->dma_sgt->sgl;
381 for (i = 0; i < sgt->orig_nents; ++i) {
382 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
387 attach->dma_dir = DMA_NONE;
388 dbuf_attach->priv = attach;
393 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
394 struct dma_buf_attachment *db_attach)
396 struct vb2_dma_sg_attachment *attach = db_attach->priv;
397 struct sg_table *sgt;
404 /* release the scatterlist cache */
405 if (attach->dma_dir != DMA_NONE)
406 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
409 db_attach->priv = NULL;
412 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
413 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
415 struct vb2_dma_sg_attachment *attach = db_attach->priv;
416 /* stealing dmabuf mutex to serialize map/unmap operations */
417 struct mutex *lock = &db_attach->dmabuf->lock;
418 struct sg_table *sgt;
423 /* return previously mapped sg table */
424 if (attach->dma_dir == dma_dir) {
429 /* release any previous cache */
430 if (attach->dma_dir != DMA_NONE) {
431 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
432 attach->dma_dir = DMA_NONE;
435 /* mapping to the client with new direction */
436 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
437 pr_err("failed to map scatterlist\n");
439 return ERR_PTR(-EIO);
442 attach->dma_dir = dma_dir;
449 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
450 struct sg_table *sgt, enum dma_data_direction dma_dir)
452 /* nothing to be done here */
455 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
457 /* drop reference obtained in vb2_dma_sg_get_dmabuf */
458 vb2_dma_sg_put(dbuf->priv);
462 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
463 enum dma_data_direction direction)
465 struct vb2_dma_sg_buf *buf = dbuf->priv;
466 struct sg_table *sgt = buf->dma_sgt;
468 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
473 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
474 enum dma_data_direction direction)
476 struct vb2_dma_sg_buf *buf = dbuf->priv;
477 struct sg_table *sgt = buf->dma_sgt;
479 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
483 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
485 struct vb2_dma_sg_buf *buf = dbuf->priv;
487 return vb2_dma_sg_vaddr(buf);
490 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
491 struct vm_area_struct *vma)
493 return vb2_dma_sg_mmap(dbuf->priv, vma);
496 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
497 .attach = vb2_dma_sg_dmabuf_ops_attach,
498 .detach = vb2_dma_sg_dmabuf_ops_detach,
499 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
500 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
501 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
502 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
503 .vmap = vb2_dma_sg_dmabuf_ops_vmap,
504 .mmap = vb2_dma_sg_dmabuf_ops_mmap,
505 .release = vb2_dma_sg_dmabuf_ops_release,
508 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
510 struct vb2_dma_sg_buf *buf = buf_priv;
511 struct dma_buf *dbuf;
512 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
514 exp_info.ops = &vb2_dma_sg_dmabuf_ops;
515 exp_info.size = buf->size;
516 exp_info.flags = flags;
519 if (WARN_ON(!buf->dma_sgt))
522 dbuf = dma_buf_export(&exp_info);
526 /* dmabuf keeps reference to vb2 buffer */
527 refcount_inc(&buf->refcount);
532 /*********************************************/
533 /* callbacks for DMABUF buffers */
534 /*********************************************/
536 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
538 struct vb2_dma_sg_buf *buf = mem_priv;
539 struct sg_table *sgt;
541 if (WARN_ON(!buf->db_attach)) {
542 pr_err("trying to pin a non attached buffer\n");
546 if (WARN_ON(buf->dma_sgt)) {
547 pr_err("dmabuf buffer is already pinned\n");
551 /* get the associated scatterlist for this buffer */
552 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
554 pr_err("Error getting dmabuf scatterlist\n");
564 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
566 struct vb2_dma_sg_buf *buf = mem_priv;
567 struct sg_table *sgt = buf->dma_sgt;
569 if (WARN_ON(!buf->db_attach)) {
570 pr_err("trying to unpin a not attached buffer\n");
575 pr_err("dmabuf buffer is already unpinned\n");
580 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
583 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
588 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
590 struct vb2_dma_sg_buf *buf = mem_priv;
592 /* if vb2 works correctly you should never detach mapped buffer */
593 if (WARN_ON(buf->dma_sgt))
594 vb2_dma_sg_unmap_dmabuf(buf);
596 /* detach this attachment */
597 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
601 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
602 unsigned long size, enum dma_data_direction dma_dir)
604 struct vb2_dma_sg_buf *buf;
605 struct dma_buf_attachment *dba;
608 return ERR_PTR(-EINVAL);
610 if (dbuf->size < size)
611 return ERR_PTR(-EFAULT);
613 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
615 return ERR_PTR(-ENOMEM);
618 /* create attachment for the dmabuf with the user device */
619 dba = dma_buf_attach(dbuf, buf->dev);
621 pr_err("failed to attach dmabuf\n");
626 buf->dma_dir = dma_dir;
628 buf->db_attach = dba;
633 static void *vb2_dma_sg_cookie(void *buf_priv)
635 struct vb2_dma_sg_buf *buf = buf_priv;
640 const struct vb2_mem_ops vb2_dma_sg_memops = {
641 .alloc = vb2_dma_sg_alloc,
642 .put = vb2_dma_sg_put,
643 .get_userptr = vb2_dma_sg_get_userptr,
644 .put_userptr = vb2_dma_sg_put_userptr,
645 .prepare = vb2_dma_sg_prepare,
646 .finish = vb2_dma_sg_finish,
647 .vaddr = vb2_dma_sg_vaddr,
648 .mmap = vb2_dma_sg_mmap,
649 .num_users = vb2_dma_sg_num_users,
650 .get_dmabuf = vb2_dma_sg_get_dmabuf,
651 .map_dmabuf = vb2_dma_sg_map_dmabuf,
652 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
653 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
654 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
655 .cookie = vb2_dma_sg_cookie,
657 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
659 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
660 MODULE_AUTHOR("Andrzej Pietrasiewicz");
661 MODULE_LICENSE("GPL");